Shoutbox

You can't change any icon-file-extension to BMP and expect it to work. For some icons this will work, for most icons, it will not. It only works for icons if they don't consist of multiple formats (an icon can hold different formats for different resolutions and colordepths) and if the format doesn't use transparency (because BMP's do not support any form of transparency)...

What you need is a simple (but good) icon-editor that can open multiple-format and/or transparency-enabled icons, and that can save to GIF, JPG, PNG, etc...

The best thing to save an high-resolution icon with transparency to is PNG, because that is the only format that fully supports alpha transparencies. PNG can be opened and edited further in a normal graphics program like PaintShopPro, PhotoShop, etc...

A very good icon-editor is:
IconXP

It can import ICO (all possible subformats of course), ICPR, BMP, JPEG, ANI, CUR, GIF, PNG, WMF, XPM, XBM, WBMP and Adobe Photoshop PSD. It can export to ICO, ICPR, BMP, JPEG, CUR, PNG, GIF, RC, XPM, XBM, WBMP and Adobe Photoshop PSD files. The UI is very intituive (unlike IrfanView) and it runs on all Windows systems...

This is a highly recommended program, one of the best in it's kind, but it is shareware (30-day trial period), but it's worth it's price more then enough.

Of course you can find similar tools all over the net. And if it is only to convert some ico's to png's, then you proberly can find some other (but less "user-friendly" but working) alternatives... But make sure the application you use supports high resolution icons with alpha transparency




btw, IrfanView isn't your best first choice, although it can open mutliple-format icons, the handling of them is very dodgy and very complicated (many mouseclicks and actions and understanding to do something) but it is free...